inconsistent (plot holes?)
So in the biggest part of the movie, when light hits Diana she disappears. But at the end, it actually burns her (if you remember the scene where her hand is burned).
AND throughout the movie we see Diana in all kinds of faint light, but when the boyfriend shows her the cellphone screen, she disappears. This two things kind of bothered me.
But all in all, I found this movie really entertaining. I wouldn't call it a masterpiece or anything, but it was scary enough to make me sleep with lights on that night :D